fsck.c

   1 #include "cache.h"
   2 #include "object.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "tree-walk.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "fsck.h"
   9 #include "refs.h"
  10 #include "utf8.h"
  11
  12 static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
  13 {
  14         struct tree_desc desc;
  15         struct name_entry entry;
  16         int res = 0;
  17
  18         if (parse_tree(tree))
  19                 return -1;
  20
  21         init_tree_desc(&desc, tree->buffer, tree->size);
  22         while (tree_entry(&desc, &entry)) {
  23                 int result;
  24
  25                 if (S_ISGITLINK(entry.mode))
  26                         continue;
  27                 if (S_ISDIR(entry.mode))
  28                         result = walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data);
  29                 else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
  30                         result = walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data);
  31                 else {
  32                         result = error("in tree %s: entry %s has bad mode %.6o",
  33                                         sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
  34                 }
  35                 if (result < 0)
  36                         return result;
  37                 if (!res)
  38                         res = result;
  39         }
  40         return res;
  41 }
  42
  43 static int fsck_walk_commit(struct commit *commit, fsck_walk_func walk, void *data)
  44 {
  45         struct commit_list *parents;
  46         int res;
  47         int result;
  48
  49         if (parse_commit(commit))
  50                 return -1;
  51
  52         result = walk((struct object *)commit->tree, OBJ_TREE, data);
  53         if (result < 0)
  54                 return result;
  55         res = result;
  56
  57         parents = commit->parents;
  58         while (parents) {
  59                 result = walk((struct object *)parents->item, OBJ_COMMIT, data);
  60                 if (result < 0)
  61                         return result;
  62                 if (!res)
  63                         res = result;
  64                 parents = parents->next;
  65         }
  66         return res;
  67 }
  68
  69 static int fsck_walk_tag(struct tag *tag, fsck_walk_func walk, void *data)
  70 {
  71         if (parse_tag(tag))
  72                 return -1;
  73         return walk(tag->tagged, OBJ_ANY, data);
  74 }
  75
  76 int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
  77 {
  78         if (!obj)
  79                 return -1;
  80         switch (obj->type) {
  81         case OBJ_BLOB:
  82                 return 0;
  83         case OBJ_TREE:
  84                 return fsck_walk_tree((struct tree *)obj, walk, data);
  85         case OBJ_COMMIT:
  86                 return fsck_walk_commit((struct commit *)obj, walk, data);
  87         case OBJ_TAG:
  88                 return fsck_walk_tag((struct tag *)obj, walk, data);
  89         default:
  90                 error("Unknown object type for %s", sha1_to_hex(obj->sha1));
  91                 return -1;
  92         }
  93 }
  94
  95 /*
  96  * The entries in a tree are ordered in the _path_ order,
  97  * which means that a directory entry is ordered by adding
  98  * a slash to the end of it.
  99  *
 100  * So a directory called "a" is ordered _after_ a file
 101  * called "a.c", because "a/" sorts after "a.c".
 102  */
 103 #define TREE_UNORDERED (-1)
 104 #define TREE_HAS_DUPS  (-2)
 105
 106 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 107 {
 108         int len1 = strlen(name1);
 109         int len2 = strlen(name2);
 110         int len = len1 < len2 ? len1 : len2;
 111         unsigned char c1, c2;
 112         int cmp;
 113
 114         cmp = memcmp(name1, name2, len);
 115         if (cmp < 0)
 116                 return 0;
 117         if (cmp > 0)
 118                 return TREE_UNORDERED;
 119
 120         /*
 121          * Ok, the first <len> characters are the same.
 122          * Now we need to order the next one, but turn
 123          * a '\0' into a '/' for a directory entry.
 124          */
 125         c1 = name1[len];
 126         c2 = name2[len];
 127         if (!c1 && !c2)
 128                 /*
 129                  * git-write-tree used to write out a nonsense tree that has
 130                  * entries with the same name, one blob and one tree.  Make
 131                  * sure we do not have duplicate entries.
 132                  */
 133                 return TREE_HAS_DUPS;
 134         if (!c1 && S_ISDIR(mode1))
 135                 c1 = '/';
 136         if (!c2 && S_ISDIR(mode2))
 137                 c2 = '/';
 138         return c1 < c2 ? 0 : TREE_UNORDERED;
 139 }
 140
 141 static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
 142 {
 143         int retval;
 144         int has_null_sha1 = 0;
 145         int has_full_path = 0;
 146         int has_empty_name = 0;
 147         int has_dot = 0;
 148         int has_dotdot = 0;
 149         int has_dotgit = 0;
 150         int has_zero_pad = 0;
 151         int has_bad_modes = 0;
 152         int has_dup_entries = 0;
 153         int not_properly_sorted = 0;
 154         struct tree_desc desc;
 155         unsigned o_mode;
 156         const char *o_name;
 157
 158         init_tree_desc(&desc, item->buffer, item->size);
 159
 160         o_mode = 0;
 161         o_name = NULL;
 162
 163         while (desc.size) {
 164                 unsigned mode;
 165                 const char *name;
 166                 const unsigned char *sha1;
 167
 168                 sha1 = tree_entry_extract(&desc, &name, &mode);
 169
 170                 has_null_sha1 |= is_null_sha1(sha1);
 171                 has_full_path |= !!strchr(name, '/');
 172                 has_empty_name |= !*name;
 173                 has_dot |= !strcmp(name, ".");
 174                 has_dotdot |= !strcmp(name, "..");
 175                 has_dotgit |= (!strcmp(name, ".git") ||
 176                                is_hfs_dotgit(name) ||
 177                                is_ntfs_dotgit(name));
 178                 has_zero_pad |= *(char *)desc.buffer == '0';
 179                 update_tree_entry(&desc);
 180
 181                 switch (mode) {
 182                 /*
 183                  * Standard modes..
 184                  */
 185                 case S_IFREG | 0755:
 186                 case S_IFREG | 0644:
 187                 case S_IFLNK:
 188                 case S_IFDIR:
 189                 case S_IFGITLINK:
 190                         break;
 191                 /*
 192                  * This is nonstandard, but we had a few of these
 193                  * early on when we honored the full set of mode
 194                  * bits..
 195                  */
 196                 case S_IFREG | 0664:
 197                         if (!strict)
 198                                 break;
 199                 default:
 200                         has_bad_modes = 1;
 201                 }
 202
 203                 if (o_name) {
 204                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 205                         case TREE_UNORDERED:
 206                                 not_properly_sorted = 1;
 207                                 break;
 208                         case TREE_HAS_DUPS:
 209                                 has_dup_entries = 1;
 210                                 break;
 211                         default:
 212                                 break;
 213                         }
 214                 }
 215
 216                 o_mode = mode;
 217                 o_name = name;
 218         }
 219
 220         retval = 0;
 221         if (has_null_sha1)
 222                 retval += error_func(&item->object, FSCK_WARN, "contains entries pointing to null sha1");
 223         if (has_full_path)
 224                 retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
 225         if (has_empty_name)
 226                 retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
 227         if (has_dot)
 228                 retval += error_func(&item->object, FSCK_WARN, "contains '.'");
 229         if (has_dotdot)
 230                 retval += error_func(&item->object, FSCK_WARN, "contains '..'");
 231         if (has_dotgit)
 232                 retval += error_func(&item->object, FSCK_WARN, "contains '.git'");
 233         if (has_zero_pad)
 234                 retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
 235         if (has_bad_modes)
 236                 retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
 237         if (has_dup_entries)
 238                 retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
 239         if (not_properly_sorted)
 240                 retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
 241         return retval;
 242 }
 243
 244 static int verify_headers(const void *data, unsigned long size,
 245                           struct object *obj, fsck_error error_func)
 246 {
 247         const char *buffer = (const char *)data;
 248         unsigned long i;
 249
 250         for (i = 0; i < size; i++) {
 251                 switch (buffer[i]) {
 252                 case '\0':
 253                         return error_func(obj, FSCK_ERROR,
 254                                 "unterminated header: NUL at offset %d", i);
 255                 case '\n':
 256                         if (i + 1 < size && buffer[i + 1] == '\n')
 257                                 return 0;
 258                 }
 259         }
 260
 261         /*
 262          * We did not find double-LF that separates the header
 263          * and the body.  Not having a body is not a crime but
 264          * we do want to see the terminating LF for the last header
 265          * line.
 266          */
 267         if (size && buffer[size - 1] == '\n')
 268                 return 0;
 269
 270         return error_func(obj, FSCK_ERROR, "unterminated header");
 271 }
 272
 273 static int fsck_ident(const char **ident, struct object *obj, fsck_error error_func)
 274 {
 275         char *end;
 276
 277         if (**ident == '<')
 278                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
 279         *ident += strcspn(*ident, "<>\n");
 280         if (**ident == '>')
 281                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad name");
 282         if (**ident != '<')
 283                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing email");
 284         if ((*ident)[-1] != ' ')
 285                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
 286         (*ident)++;
 287         *ident += strcspn(*ident, "<>\n");
 288         if (**ident != '>')
 289                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad email");
 290         (*ident)++;
 291         if (**ident != ' ')
 292                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before date");
 293         (*ident)++;
 294         if (**ident == '0' && (*ident)[1] != ' ')
 295                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - zero-padded date");
 296         if (date_overflows(strtoul(*ident, &end, 10)))
 297                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - date causes integer overflow");
 298         if (end == *ident || *end != ' ')
 299                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad date");
 300         *ident = end + 1;
 301         if ((**ident != '+' && **ident != '-') ||
 302             !isdigit((*ident)[1]) ||
 303             !isdigit((*ident)[2]) ||
 304             !isdigit((*ident)[3]) ||
 305             !isdigit((*ident)[4]) ||
 306             ((*ident)[5] != '\n'))
 307                 return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad time zone");
 308         (*ident) += 6;
 309         return 0;
 310 }
 311
 312 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 313         unsigned long size, fsck_error error_func)
 314 {
 315         unsigned char tree_sha1[20], sha1[20];
 316         struct commit_graft *graft;
 317         unsigned parent_count, parent_line_count = 0;
 318         int err;
 319
 320         if (verify_headers(buffer, size, &commit->object, error_func))
 321                 return -1;
 322
 323         if (!skip_prefix(buffer, "tree ", &buffer))
 324                 return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
 325         if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
 326                 return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
 327         buffer += 41;
 328         while (skip_prefix(buffer, "parent ", &buffer)) {
 329                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
 330                         return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
 331                 buffer += 41;
 332                 parent_line_count++;
 333         }
 334         graft = lookup_commit_graft(commit->object.sha1);
 335         parent_count = commit_list_count(commit->parents);
 336         if (graft) {
 337                 if (graft->nr_parent == -1 && !parent_count)
 338                         ; /* shallow commit */
 339                 else if (graft->nr_parent != parent_count)
 340                         return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
 341         } else {
 342                 if (parent_count != parent_line_count)
 343                         return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
 344         }
 345         if (!skip_prefix(buffer, "author ", &buffer))
 346                 return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
 347         err = fsck_ident(&buffer, &commit->object, error_func);
 348         if (err)
 349                 return err;
 350         if (!skip_prefix(buffer, "committer ", &buffer))
 351                 return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'committer' line");
 352         err = fsck_ident(&buffer, &commit->object, error_func);
 353         if (err)
 354                 return err;
 355         if (!commit->tree)
 356                 return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
 357
 358         return 0;
 359 }
 360
 361 static int fsck_commit(struct commit *commit, const char *data,
 362         unsigned long size, fsck_error error_func)
 363 {
 364         const char *buffer = data ?  data : get_commit_buffer(commit, &size);
 365         int ret = fsck_commit_buffer(commit, buffer, size, error_func);
 366         if (!data)
 367                 unuse_commit_buffer(commit, buffer);
 368         return ret;
 369 }
 370
 371 static int fsck_tag_buffer(struct tag *tag, const char *data,
 372         unsigned long size, fsck_error error_func)
 373 {
 374         unsigned char sha1[20];
 375         int ret = 0;
 376         const char *buffer;
 377         char *to_free = NULL, *eol;
 378         struct strbuf sb = STRBUF_INIT;
 379
 380         if (data)
 381                 buffer = data;
 382         else {
 383                 enum object_type type;
 384
 385                 buffer = to_free =
 386                         read_sha1_file(tag->object.sha1, &type, &size);
 387                 if (!buffer)
 388                         return error_func(&tag->object, FSCK_ERROR,
 389                                 "cannot read tag object");
 390
 391                 if (type != OBJ_TAG) {
 392                         ret = error_func(&tag->object, FSCK_ERROR,
 393                                 "expected tag got %s",
 394                             typename(type));
 395                         goto done;
 396                 }
 397         }
 398
 399         if (verify_headers(buffer, size, &tag->object, error_func))
 400                 goto done;
 401
 402         if (!skip_prefix(buffer, "object ", &buffer)) {
 403                 ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'object' line");
 404                 goto done;
 405         }
 406         if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 407                 ret = error_func(&tag->object, FSCK_ERROR, "invalid 'object' line format - bad sha1");
 408                 goto done;
 409         }
 410         buffer += 41;
 411
 412         if (!skip_prefix(buffer, "type ", &buffer)) {
 413                 ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'type' line");
 414                 goto done;
 415         }
 416         eol = strchr(buffer, '\n');
 417         if (!eol) {
 418                 ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
 419                 goto done;
 420         }
 421         if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
 422                 ret = error_func(&tag->object, FSCK_ERROR, "invalid 'type' value");
 423         if (ret)
 424                 goto done;
 425         buffer = eol + 1;
 426
 427         if (!skip_prefix(buffer, "tag ", &buffer)) {
 428                 ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'tag' line");
 429                 goto done;
 430         }
 431         eol = strchr(buffer, '\n');
 432         if (!eol) {
 433                 ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
 434                 goto done;
 435         }
 436         strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 437         if (check_refname_format(sb.buf, 0))
 438                 error_func(&tag->object, FSCK_WARN, "invalid 'tag' name: %.*s",
 439                            (int)(eol - buffer), buffer);
 440         buffer = eol + 1;
 441
 442         if (!skip_prefix(buffer, "tagger ", &buffer))
 443                 /* early tags do not contain 'tagger' lines; warn only */
 444                 error_func(&tag->object, FSCK_WARN, "invalid format - expected 'tagger' line");
 445         else
 446                 ret = fsck_ident(&buffer, &tag->object, error_func);
 447
 448 done:
 449         strbuf_release(&sb);
 450         free(to_free);
 451         return ret;
 452 }
 453
 454 static int fsck_tag(struct tag *tag, const char *data,
 455         unsigned long size, fsck_error error_func)
 456 {
 457         struct object *tagged = tag->tagged;
 458
 459         if (!tagged)
 460                 return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
 461
 462         return fsck_tag_buffer(tag, data, size, error_func);
 463 }
 464
 465 int fsck_object(struct object *obj, void *data, unsigned long size,
 466         int strict, fsck_error error_func)
 467 {
 468         if (!obj)
 469                 return error_func(obj, FSCK_ERROR, "no valid object to fsck");
 470
 471         if (obj->type == OBJ_BLOB)
 472                 return 0;
 473         if (obj->type == OBJ_TREE)
 474                 return fsck_tree((struct tree *) obj, strict, error_func);
 475         if (obj->type == OBJ_COMMIT)
 476                 return fsck_commit((struct commit *) obj, (const char *) data,
 477                         size, error_func);
 478         if (obj->type == OBJ_TAG)
 479                 return fsck_tag((struct tag *) obj, (const char *) data,
 480                         size, error_func);
 481
 482         return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
 483                           obj->type);
 484 }
 485
 486 int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
 487 {
 488         va_list ap;
 489         struct strbuf sb = STRBUF_INIT;
 490
 491         strbuf_addf(&sb, "object %s:", sha1_to_hex(obj->sha1));
 492
 493         va_start(ap, fmt);
 494         strbuf_vaddf(&sb, fmt, ap);
 495         va_end(ap);
 496
 497         error("%s", sb.buf);
 498         strbuf_release(&sb);
 499         return 1;
 500 }